British Citizen in Norway

1. You should fill Form A & B online first, and then print them out. You are right you need to fill and provide Form B as an Alien in Norway.
2. Seems that no advance appointment is required, and you may just walk into the visa office to sumit your application or authorize a third party on your behalf during their office hours.
3. For business, you also need to provide photocopy of your Residence Permit issued by UDI valid for at least 6 months, Letter of employment or your Employment card from a Norwegian company, a letter of invitation issued by a Chinese company indicating the purpose of this trip, the times of entries to be applied for, the invitee’s personal information such as name, birth date , passport number and the company's contact information i.e. office address, telephone number, etc. The company's registration stamp and the signature from the person in charge is required as well.